1. Field of Invention
The present invention relates to a conductive connection structure for secondary batteries and more particularly to a connection structure for battery cells and an anode terminal or a cathode terminal on a battery cover plate inside a secondary battery.
2. Related Art
Because of breakthroughs in materials technology for lithium batteries, secondary batteries have become a power supplies source (e.g. lithium iron phosphate oxide) for devices which require large electricity consumption such as electric bikes and electric wheelchairs. The power storage quantity and power supply quantity of non-aqueous electrolytic secondary lithium batteries are larger than those of conventional lithium battery.
Referring to FIG. 1, it shows a conventional high capacity rectangular secondary battery, which comprises a plurality of battery cells 10 (three battery cells 10 are shown in the figure for an example). Each of the battery cells 10 is composed of an anode layer, a separating layer and a cathode layer superimposed together, and an anode terminal 11 and a cathode terminal 12 are respectively disposed on two lateral sides of each of the battery cells 10. The battery cells 10 are electrically connected to two conductive portions 21, 22 disposed under two lateral sides of a cover plate 20 via the anode terminal and the cathode terminal 11, 12. In addition, the conductive portions 21, 22 penetrate through the cover plate 20 and electrically connect to electrodes 31, 32 on the cover plate 20 respectively, so as to form a conductive connection structure for external conductive connections. Lastly, the battery cells 10 are placed inside a casing 40 made of metals, then the cover plate 20 and the casing 40 are combined and sealed around the edges thereof by various sealing means, as a result, the rectangular secondary battery is manufactured.
However, in an internal structure of the conventional secondary battery, the conductive portions 21, 22 under the cover plate 20 are disposed vertically to a bottom surface of the cover plate 20, and the battery cells 10 are soldered or connected with the conductive portions 21, 22 via the anode terminals 11 and the cathode terminals 12 which are also disposed vertically to the surface of the cover plate 20. Therefore, the conductive portions 21, 22 need to be structurally matched with a quantity of the battery cells 10; three battery cells 10 shown in the figure are used as an example, that means there are three conductive portions 21, 22 at two lateral sides of the battery cells 10 respectively; therefore, each of the battery cells 10 needs to be soldered or connected to the conductive portions 21, 22 one by one, via the anode terminals 11 and the cathode terminals 12. However, the soldering or connecting process is not only labor and time consuming, but it is difficult for the anode terminals 11/the cathode terminals 12 and the conductive portions 21, 22 to have a tighten electrical connection, which could be rather troublesome for smooth assembling.